High bandwidth delivery and internet access for airborne passengers

ABSTRACT

A method and a communications system in which a request for data transmitted by an airborne transmitter over a low-bandwidth air-to-ground communication system uplink and received by a ground-based receiver. The requested data is then transmitted over a high-bandwidth communication system downlink, such as a DBS satellite system downlink, preferably using an MPEG-2 compression technique, and received by an airborne receiver located on the same aircraft as the airborne transmitter. The received request for data is transmitted to a data network that contains the requested data, such as the Internet or a private data network, using circuit-switched techniques. According to the invention, the requested data includes one of video information, audio information and textual information.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to application Ser. No. 08/989,623,filed concurrently, and commonly assigned with the present invention andnow abandoned.More than one reissue application has been filed inconnection with U.S. Pat. No. 6,201,797 entitled “HIGH BANDWIDTHDELIVERY AND INTERNET ACCESS FOR AIRBORNE PASSENGERS.” This reissueapplication is a continuation of co-pending U.S. Reissue applicationSer. No. 10/389,010, which was filed on Mar. 13, 2003. Reissueapplication Ser. No. 11/296,743, now U.S. Reissue Pat. No. RE40,476, wasfiled on Dec. 6, 2005, and is also a continuation of U.S. Reissueapplication Ser. No. 10/389,010. Each of these applications are herebyincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of telecommunications. Moreparticularly, the present invention relates to a method and to a systemfor communicating between an airborne data terminal and a ground-basedcomputer network.

2. Description of Related Art

The ability for passengers on a commercial airline flight to make phonecalls is well-known. Initially, such airborne telephone calls utilizedan analog technology that was similar to that used by an airborne radiostation broadcasting a modulated voice signal over a designatedfrequency to a ground-based station. The ground station interfaced witha Public Switched telephony Network (PSTN) to complete the call. Theanalog approach suffers from problems associated with signaldegradation, and requires a relatively large bandwidth for carrying avoice band signal.

An all digital air-to-ground telephony network service was introduced in1993 in which voice signals are carried by an ISDN link on an aircraftto a radio link. Modern digital transmission and speech processingtechniques are used on the voice signals before an airborne radiotransmitter transmits an encoded digital voice signal to the groundwhere the voice signal is routed to the PSTN. The digital approachdelivers a clearer voice quality than the analog approach, and allowsevolving speech encoding techniques to carry more simultaneous voicecalls over available communication channels.

At the time the all digital air-to-ground service was introduced, theonly data service envisioned was facsimile and data modem-type calls tobe made to ground-based stations or terminals. To accommodate existingfacsimile and data modems that might be used on an aircraft for sendingfacsimile documents or for retrieving e-mail messages, a voice encoderon the aircraft used for voice calls is bypassed with a proper rateadaptation so that modem signals are send over the radio link. Still,this type of connection is considered to be a circuit-switched voicecall, that is, each dialup consumes one standard voice channel. As aresult, the tariff for a conventional airborne data service call is thesame as the tariff for a standard voice call because the procedure forsetting up the two types of calls is the same, and the bandwidth that isconsumed by a conventional airborne data call is the same as thebandwidth consumed by a standard voice call. Further, the types of dataservices that are conveniently available through conventional airbornedata service calls are severely limited because of the limited bandwidthavailable for a conventional airborne data call. For example,conventional airborne data services do not provide a bandwidth that issufficient for supporting, for example, access to the Internet in whichgraphics, audio, video, textual and multimedia content are available.

What is needed is a way to provide an integrated voice/data service toairborne passengers that can mix various data services, such asaccessing the Internet or placing a voice call, and thereby utilize thelimited air channels available to airborne passengers more efficiently.

SUMMARY OF THE INVENTION

The present invention provides a method and a communications system thatprovides an integrated voice/data service to airborne passengers thatcan mix various data services, such as accessing the Internet or placinga voice call, and thereby efficiently utilizing the air channelsavailable to airborne passengers.

The advantages of the present invention are provided by a method and acommunications system in which a request for data transmitted by anairborne transmitter over a low-bandwidth air-to-ground communicationsystem uplink and received by a ground-based receiver. The requesteddata is then transmitted over a high-bandwidth communication systemdownlink, such as a DBS satellite system downlink, preferably using anMPEG-2 compression technique, and received by an airborne receiverlocated on the same aircraft as the airborne transmitter. The receivedrequest for data is transmitted to a data network that contains therequested data, such as the Internet or a private data network, usingcircuit-switched techniques. The requests from all active data users aremultiplexed on the same circuit-switched channel, thus conserving thebandwidth for normal voice channels. According to the invention, therequested data includes one of video information, audio information andtextual information.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and notlimitation in the accompanying figures in which like reference numeralsindicate similar elements and in which:

FIG. 1 shows a schematic block diagram of a telecommunications systemthat provides an air-to-ground communication link between an airbornetelecommunication data terminal and a ground-based network according tothe present invention; and

FIG. 2 is a diagram of a preferred configuration of a telecommunicationssystem providing an NATS-type packet data network uplink and a DBS-typesystem downlink according to the present invention.

DETAILED DESCRIPTION

The present invention provides a method and a system providing twowaydata communications between an airborne data terminal station, such as apersonal computer (PC) or a laptop computer, and a ground-based datanetwork, such as the Internet, using a packet data switching technology.As a result, the present invention utilizes available air-to-groundbandwidth more efficiently than conventional airborne datatelecommunications systems because the same air-to-ground channel isused for multiplexing data packets from different concurrent user datasessions.

FIG. 1 shows a schematic block diagram of a telecommunications system 10that provides an air-to-ground communication link between an airbornedata terminal 11, such as a PC or a laptop computer, and a ground-basednetwork 2, such as the Internet. According to the invention, system 10is located on an airborne platform, such as an airplane, a helicopter ora space vehicle, and includes a data transport mechanism, a data servermechanism and an Application Programming Interface (API) function. TheAPI function is used by an external application for interacting with thedata server mechanism for call control functions and for performingOperation, Administration, Maintenance and Provisioning (OAM&P)functions.

The data transport mechanism provides interfaces to and includes variousdata pipes that are both internal and external to the aircraft. Theinternal data pipes link passengers and aircraft personnel to a dataserver. According to the invention, the internal data pipes can be anyof an existing Cabin Distribution System (CDS) using an IntegratedServices Digital Network (ISDN), a Local Area Network (LAN), an Ethernetor a Fiber Distributed Data Interface (FDDI) network, and/or anAsynchronous Tranmission Mode (ATM) network for distributing video,voice/audio, and textual data signals to a display screen located, forexample, on the back of passenger seats. Preferably, an ATM internaldata pipe uses an embedded open standard Operating System, such as JAVA.

The external pipes can be various wireless pipes, or air links, to aground-based station or gateway, or to a satellite system. According tothe invention, the different external pipes that can be used with thepresent invention can be an existing terrestrial link system, such asthe North American Terrestrial System (NATS) or the European TerrestrialFlight Telephone System (TFTS), a direct air link to a terrestrialgateway, a link to a Low Earth Orbit (LEO) and/or a Medium Earth Orbit(MEO) satellite system, and/or a link to one of the emerging broadbandSatellite-based systems, such as the Digital Broadcast Satellite (DBS)or Teledesic systems.

In FIG. 1, system 10 includes a plurality of airborne data terminals 11,each of which are connected to a data server 12 by an internal data pipe13, such as an Ethernet, in a well-known manner. Data terminals 11 canbe data terminals 11a, 11b and 11c that are used by flight crew andpersonnel and data terminals 11e, 11f and 11g that are used bypassengers. For example, data terminal 11a is located on the flight deckof the aircraft, while data terminals 11b and 11c are located elsewherein the aircraft and are used by a maintenance crew and/or members of theflight crew not located on the flight deck. Data terminals 11d, 11e and11f are dedicated data terminals provided on-board the aircraft for theconvenience of passengers and/or can be portable or laptop computersprovided by passengers.

Data server 12 acts as an intelligent airborne gateway and performsmultiplexing and necessary call control functions. More specifically,data server 12 provides three general functions: 1) controlling variousdata transport interfaces; 2) multiplexing, routing, and priorityqueuing functions for data packets; and 3) updating and maintainingvarious databases depending on the application as an off-line processand for providing a uniform user interface capability (API) to clientapplications. Examples of off-line processes provided by data server 12are a HyperText Transport Protocol (HTTP) process that provides aninterface for Web browsing and an Aircraft Condition Monitoring System(ACMS) process for collecting aircraft flight data for OA&M purposes.

Data server 12 preferably includes a network interface circuit (NIC) 14,a router 15, a database 16, and at least one and preferably a pluralityof data transport interface circuits 17-20. Network interface circuit 14connects data server 12 to internal data pipe 13 in a well-known manner,and provides data packets received from data pipe 13 to router 15.Router 15 uses a routing table that is stored in routing table database16 for directing data packets received from terminals 11a-11f and voicepackets from telephones (not shown) to an appropriate data transportinterface circuit 17-20 based on a requested data service for subsequenttransmission to a particular bearer service. The components forming dataserver 12 can be physically enclosed within one housing or enclosure, orcan be physically located in separate housings that are distributedaround the aircraft depending on the technology used, the applications,and the physical constraints of the aircraft.

In FIG. 1, gate link interface circuit 17 provides well-known interfacefunctions for an air link through an antenna 21 directly to aground-based gateway 22. Gateway 22 is connected to data network 2, suchas the Internet. Similarly, Satellite Interface Circuit (SIC) 18provides well-known interface functions for an air link through anantenna 23 to a satellite network 24, such as an LEO or MEO satellitesystem. Satellite network 24 is connected to data network 2 through aground station 24a that is a part of network 24. Exemplary satellitenetworks suitable for satellite network 24 include several LEO/MEOsystems that are designed primarily for voice service, such as theIridium, Globalstar, ICO and Odyssey systems. The data service providedby these exemplary satellite systems is supported only as asupplementary service having a bit rate between 1.2 to 9.6 Kbps usingvoice band modem signaling similar to the conventional two-way dataservices available from the NATS, TFTS and SATCOM.

NATS interface circuit 19 provides well-known interface functions for anair link through an Aircraft Communication Unit (ACU) 496 NATS unit 25and an antenna 26 to a gateway 27 of an NATS-type system 31, such asAT&T's NATS network. NATS-type system 31 is connected to data network 2using a packet data transport mechanism. The AT&T's NATS networkincludes approximately 150 ground stations covering the entirecontinental United States and parts of the Canada and Mexico. All NATSground stations are interconnected to a switching center located in NewJersey from where voice traffic is routed to a PSTN. The NATS groundstations are also interconnected through a frame relay network to datacenters, or gateways, where the data packets are routed to a privatedata network or to public data network 2, such as the Internet. Using amodern protocol, such as MPP combined with PPTP or L2TP, the NATSnetwork supports an aggregated dynamic bandwidth of up to 290 Kbps in achannel block of 29 channels, subject to channel availability.

DBS decoder interface circuit 20 provides well-known interface functionsfor an air link through an antenna 28 to a DBS satellite system 29. DBSsatellite system 29 is connected to data network 2. The broadbandsatellite systems, such as the Geo-synchronous Earth Orbit (GEO) DigitalBroadcast Satellite (DBS), are envisioned as providing a one-way dataservice as the primary service. DBS technology uses an MPEG-2 digitalcompression system for sending a plurality of channels of digitizedvideo signals through one transponder. The MPEG-2 digital compressionsystem can be used for multiplexing any digital signal, including apacket data signal, and for intermixing a digital signal with a videosignal for satellite broadcasting. From the point of view of the DBSsystem is concerned, there is no difference whether a transported signalis a compressed video signal or a sequence of IP packets.

Antenna 28 used on the aircraft must be a moving or a phased-arrayantenna for maintaining a line-of-sight with a transmitting satellitebecause DBS system is a GEO satellite system. An antenna of this type isrelatively more costly than a standard fixed antenna. For othersatellite systems, such as the Low Earth Orbit (LEO) satellites that arenot geo-synchronous, the satellite system handles handoffs, therefore,eliminating the need for a moving-type antenna for antenna 23.

To provide an interactive airborne data service, such as e-mailretrieval or Web browsing, the present invention uses an NATS-typepacket data network, such as the AT&T NATS, for an uplink data pipe anda DBS-type system for a downlink data pipe. For a typical application,the relative size, or bandwidth requirement, of the data request issmall, while the amount of data returned in response to the request isrelatively large. The capability of the NATS link is sufficient forcarrying a request for data, but is insufficient for carrying therequested data. Alternatively, the uplink data pipe can be through anLEO/MEO satellite network 24, with the downlink data pipe being throughDBS-type system 29.

FIG. 2 is a diagram of a preferred configuration of a telecommunicationssystem providing an NATS-type packet data network uplink data pipe and aDBS-type system downlink data pipe according to the present invention.System 10 uses an MPP technique that aggregates multiple on-demand 9.6Kbps bandwidth upstream links from aircraft 40 to NATS system 31.Downstream links in excess of 5 Mbps bandwidth from the network areprovided through the DBS system to the aircraft. IP packets areencapsulated by lower layer protocols so that there is a transparentconduit for IP packets to be transported from the aircraft to a desiredhost and from a host to the aircraft via a DBS link.

In FIG. 2, a user using a laptop computer on airplane 40 that isconnected to system 10 sends an uplink data request for establishing ahigh-speed data session through NATS system 31. The request is sentthrough a second gateway 32 to a desired access management server 33.After a proper authentication process and channel assignment, accessmanagement server 33 sends a service initiation acknowledgement messageto the laptop computer via NATS system 31 and terrestrial gateway 27.The laptop computer receives the service initiation acknowledgementmessage via NATS interface circuit 19, router 15 and internal data pipe13 (FIG. 1). The laptop computer sends a request to a particular websiteon Internet 2 via NATS system 31. The desired website responds to thedata request by sending the data requested to an access managementserver 33 that is connected to a DBS system 29. The requested data istransmitted from a ground station 29a to DBS satellite 29b, then toaircraft 40. The laptop computer receives the requested data from DBSinterface circuit 20, router 15 and internal data pipe 13.

System 10 utilizes the advantages of the data compression features ofDBS system 29 when downloading broadband data from a DBS satellite. Anexemplary application that can be utilized by a flight crew is softwaredownloading, flight information updates, etc. In-Flight Entertainment(IFE) services offered by an airline can receive real-time videoprograms from a direct television-type service, or by allowingpassengers to browse the Internet with ample bandwidth.

Presently, the available DBS systems are broadcast-only systems. When atwo-way DBS satellite link is available, data server 12 will treat suchan uplink as another bearer service and uses the satellite broadbandnetwork for interconnecting aircraft 40 to a ground-based gateway. Thebandwidth available with the two-way broadband satellite systemssupports applications, such as video conferencing, high-quality video,high-speed Internet, and virtual LAN to the aircraft. An added advantageof using any of satellite systems 24, 29 is that universal access ispossible so that the same system can be used anywhere on earth. For thisembodiment of the present invention, the satellite network is connectedto the mobile terminal on-board the aircraft, handling routing andhandoffs needed for linking the mobile terminal on-board the aircraft toa ground-based gateway in a well-known manner similar to that used byconventional cellular telephone system, instead of a network of groundstations that connect the gateway. As long as an aircraft and a gatewaycan connect by way of a satellite network, SVCs or PVCs can be set upbetween any pair of terminal stations. For example, one aircraft canhave an SVC to another aircraft as long as both aircraft are serviced bythe satellite system. Similarly, an aircraft can have an SVC to anygateway as long as both can be connected through the satellite system.

The API function of the present invention is provided by a collection ofAPIs or procedures having a standardized execution environment, and canbe executed by applications, whether local or remote, for allowing theconfiguration of call/data routes, monitoring and reporting ofactivities, and messaging and presentation of data to users. An exampleof an API that can be used with the present invention are JAVA appletsthat can be executed by any JAVA-capable Web browser for allowing aflight crew to view the latest gate link information or for groundcontrol personnel to view the vital statistics of the aircraft in realtime.

The API function of the present invention is the enabling tool forallowing quick introduction of new applications and/or services, fordeveloping specific applications for call monitoring and controlpurposes, and for incorporating new technologies without significantdevelopment effort. The APIs used with the present invention are highlymodularized so that any combination of APIs can be incorporated intocreating new applications without having impact on existingapplications.

Preferably, the present invention uses the TCP/IP protocol as anetworking protocol, thus allowing interconnection to virtually anynetwork. An additional advantage of the present invention is that theability to access to the vast collection of TCP/IP protocols, tools andapplications provides the present invention with the flexibility to meetthe needs of future aircraft data services. The present invention isexpandable by providing an infrastructure that is modularized and isdesigned to use Open System interfaces, allowing new hardware andtechnologies to be incorporated with minimal development. Preferably,the present invention uses COTS hardware and software.

1. A method for air to ground communication, comprising the steps of:(a) transmitting a request for a data session from an air borne terminalvia an airborne transceiver and first antenna using a low bandwidthdownlink to a ground based gateway linked to a server connected to adata network; (b) transmitting a service initiation acknowledgement fromthe server to the airborne terminal via the ground based gateway, thelow bandwidth downlink, the airborne transceiver and first antenna; (c)transmitting a data request from the airborne terminal to the datanetwork via the airborne transceiver and first antenna, low bandwidthdown link, the ground based gateway and the server; and (d) transmittingthe requested data from the data network to the airborne terminal via ahigh bandwidth satellite uplink, an airborne receiver and secondantenna.
 2. The method according to claim 1, wherein the uplink is partof a DBS satellite system.
 3. The method according to claim 1, whereinthe data network is the Internet.
 4. The method according to claim 1,wherein the data network is a private network.
 5. The method accordingto claim 1, wherein the step of transmitting the requested data over thehigh-bandwidth communication system uplink includes the step of using anMPEG-2 compression technique for transmitting the requested data overthe high-bandwidth communication system uplink using the second antenna.6. The method according to claim 1, wherein the requested data includesone of video information, audio information and textual information. 7.The method of claim 1 further comprising the step of: (e) using anaccess management server to obtain the requested data from the datanetwork and transmit the requested data to the airborne terminal via thehigh bandwidth satellite uplink and the airborne receiver and secondantenna.
 8. An air to ground communication system, comprising (a) anairborne terminal coupled to an airborne transceiver and first antenna;(b) a low bandwidth downlink provided by the airborne transceiver andfirst antenna; (c) a ground based gateway for receiving the lowbandwidth down link; (d) a data network coupled to the ground basedgateway via a server; (e) a high bandwidth satellite uplink coupled tothe data network; and (f) an airborne receiver and second antennacoupled to the uplink whereby a data request from the airborne terminalis transmitted to the data network via the airborne transceiver andfirst antenna, the low bandwidth down link, the ground based gateway andthe server and the requested data is transmitted by the data network tothe airborne terminal via the high bandwidth satellite uplink and theairborne receiver and second antenna.
 9. The system according to claim8, wherein the uplink is part of a DBS satellite system.
 10. The systemaccording to claim 8, wherein the data network is the Internet.
 11. Thesystem according to claim 8, wherein the data network is a privatenetwork.
 12. The system according to claim 8, wherein the DBS satellitesystem uses an MPEG-2 compression technique for transmitting therequested data over the high-bandwidth communication system uplink usingthe second antenna.
 13. The system according to claim 8, wherein therequested data includes one of video information, audio information andtextual information.
 14. The system of claim 8 further comprising: (g)an access management serve, coupled to the data network for obtainingand transmitting the requested data via the high bandwidth satelliteuplink and the airborne receiver and second antenna.
 15. Anair-to-ground communication system for use with an airborne computer,the air-to-ground communication system comprising: an airbornetransmitter coupled with the airborne computer, wherein the airbornetransmitter is further coupled with a low-bandwidth communication link,and wherein the airborne transmitter is configured to provide a requestfor ground-based data by the airborne computer over the low-bandwidthcommunication link; an airborne receiver coupled with a high-bandwidthcommunication link, wherein the airborne receiver is further configuredto receive the requested ground-based data over the high-bandwidthcommunication link; an airborne data server mechanism configured toprovide the requested ground-based data to the airborne computer, theairborne data server mechanism controls at least one of the airbornetransmitter or the airborne receiver; an airborne applicationprogramming interface (API) configured to communicate with the airbornecomputer and the airborne data server mechanism; and an airborne datatransport mechanism at least logically coupling the low-bandwidthcommunication link, the airborne data server mechanism, and thehigh-bandwidth communication link to facilitate delivery of therequested ground-based data to the airborne computer based on therequest for the ground-based data by the airborne computer.
 16. Thesystem according to claim 15 wherein the high-bandwidth communicationlink is a satellite communications channel.
 17. The system according toclaim 15 wherein the low-bandwidth communication link is a satellitecommunications channel.
 18. The system according to claim 15 wherein thereceiver and transmitter are a single transceiver.
 19. An air-to-groundcommunication system for use with a portable airborne computer, theair-to-ground communication system comprising: data server means forproviding data to, and being coupled with, the portable airbornecomputer, wherein the data server means is configured to be locatedwithin an aircraft; wherein the data server means is configured toreceive a request for ground-based data from the portable airbornecomputer; data transport means for communicating with a wirelessground-to-air communication channel, a wireless air-to-groundcommunication channel, the data server means, and the airborne computer;wherein the data transport means is configured to receive the requestfor the ground-based data, and provide the request for the ground-baseddata to the wireless air-to-ground communication channel; and whereinthe data server means is configured to receive the requestedground-based data from the wireless ground-to-air communication channel,to facilitate delivery of the requested ground-based data to theportable airborne computer, and to control the data transport means. 20.The air to around communication system of claim 19, further comprising:application programming interface (API) means configured to communicatewith the portable airborne computer and the data server means.
 21. Theair-to-ground communication system of claim 19, further comprising:airborne transmitter means coupled with the data transport means,wherein the wireless air-to-ground communication channel includes alow-bandwidth communication link.
 22. The air-to-ground communicationsystem of claim 19, further comprising: airborne receiver means coupledwith the data transport means, wherein the wireless ground-to-aircommunication channel includes a high-bandwidth communication link. 23.An air-to-ground communication system for use with an airborne computer,the air-to-ground communication system comprising: an air bornetransmitter means coupled with the airborne computer, the airbornetransmitter means for providing a request for ground based data by theairborne computer over a low-band width communication link; an airbornereceiver means coupled with a high-bandwidth communication link, theairborne receiver means for receiving requested ground based data overhigh bandwidth communication link; an airborne data server means forproviding the requested ground based data to the airborne computer; anairborne application programming interface means for interfacingcommunication with the airborne transmitter means and the airbornereceiver means; and an airborne data transport means for logicallycoupling together the low-bandwidth communication link, the airbornetransmitter means and the high-bandwidth communication link, tofacilitate delivery of the requested ground based data to the airbornecomputer.
 24. The system according to claim 23, wherein thehigh-bandwidth ground-to-air communication link includes a satellitecommunications channel.
 25. The system according to claim 23, whereinthe low-bandwidth air-to-ground communication link includes a satellitecommunications channel.
 26. The system according to claim 23, whereinthe low-bandwidth air-to-ground communication link is received from afirst airborne antenna associated with an aircraft, and thehigh-bandwidth ground-to-air communication link is associated with asecond airborne antenna associated with the aircraft.